1. Field of Invention
The invention relates to an improvement to a piano key assembly for a pianoforte (grand piano) having weighted keysticks to achieve an improved dynamic response.
2. Description of Prior Art
The technique of keystick balancing for a pianoforte (that is, a grand piano) has seen little change in the past 100 years. U.S. Pat. No. 633,915 to Smith teaches the placement of lead weights within the keystick to balance a key in such manner as to make it properly responsive to the touch of the pianist. More recently, U.S. Pat. No. 5,585,582 to Stanwood (“Stanwood 1”) teaches a method to determine the proper amount of off-setting weight to place within a keystick during manufacturing to provide a more uniform feel when playing. U.S. Pat. No. 5,796,024 to Stanwood (“Stanwood 2”) teaches a method for fixing the amount of off-setting weight and varying an additional calibration weight to achieve the desired balance. U.S. Pat. No. 6,096,959 to Davide applies keystick balancing to an upright piano key mechanism with the addition of lead weights to the keystick and the wippen. U.S. Pat. No. 6,531,651 to Kanemitser et al. discloses a musical instrument key with a means for simplifying the adjustment of weights.
Conventional balancing methods and recent improvements such as these focus on the static balance of the keystick and ignore the effect weigh-off has on the internal inertia of the key. Lead weights placed near the “ivory end” of keystick require the piano player to move the weights a greater distance at a greater speed than if the weight were placed closer to the pivot point (fulcrum). (As used hereinafter, the term “ivory end” of a keystick is intended to denote the end of the keystick that is pressed down by the finger(s) of a piano player, regardless of whether the keystick does or does not have “ivory”, or whether the keystick is or is not associated with a “white” key or “black” key.) Stanwood 2 and Davide, both improvements to the teaching of Stanwood 1, increase the keystick inertia with the addition of more weight. While both may create an instrument with keysticks uniformly balanced, the dynamic performance of the instrument is negatively impacted by the increased inertia.
U.S. Pat. No. 2,031,748 to Vietor discloses a technique for balancing the keys of a piano keyboard by the placement of lead weights in the keysticks. Unlike the other prior art references, this patent is concerned with the placement of off-setting weights to maximally reduce the inertia of the keys. In particular, this patent teaches the placement of a large weight and small weight immediately adjacent the pivot point of the keystick. While this arrangement does, indeed, reduce the inertia to an absolute minimum, it does not provide sufficient off-setting weight for a piano key.
My earlier invention, as expressed and claimed in my U.S. Pat. No. 7,186,907, teaches providing a piano key assembly for a pianoforte—that is, a grand piano—which is optimally balanced, using lead weights, for improved “feel” and performance of the instrument. The content of U.S. Pat. No. 7,186,907 is incorporated herein by reference in its entirety. This is accomplished by property locating the center of gravity of the lead weights along each keystick of the key assembly and adjusting the amount of weight for optimal static and dynamic performance of the pianoforte. More particularly, the center of gravity of the weights is arranged along each keystick between a first point, halfway between the pivot point and the ivory end of the keystick, and a second point along the keystick halfway between the first point and the pivot point. The amount of weight applied at this center of gravity is preferably adjusted so that the average of the static downweight and upweight for each keystick is in the range of 10 to 20 grams heavier than the conventionally accepted value for that keystick on a keyboard.